Analysis of the variability of a new angular measurement for hallux valgus Andrés Keller, Emilio Wagner, Cristian Ortiz, Francisco García, Ignacio Villalón, Juan Valderrama, Ignacio Toledo. Departament of Orthopaedic Facultad de Medicina Universidad del Desarrollo / Clínica Alemana
Analysis of the variability of a new angular measurement for Hallux Valgus Andrés Keller MD My disclosure is in the Final AOFAS Program Book and in the Orthopaedic Surgeon s Disclosure Program database. I have no potential conflicts with this presentation
Introduction: Intermetatarsal angle (IMTT): is the most common objective parameter used for selecting procedures to treat HV Wolfgang Sch., et al. Reproducibility of the radiographic metatersophalangeal angle in hallux surgery. JBJS Am. 2003 Angle to be corrected: A new angle measured between a line representing the first metatarsal axis and a line drawn from the base of the first metatarsal passing distally through the midpoint of the sesamoid complex. Represents the angular correction needed to place the metatarsal head over the sesamoid complex Wagner E., et al. Modified diaphyseal osteotomy with a proximal center of rotation for moderate to severe hallux valgus. TFAS 2007.
Objective: To evaluate interobserver variability for the measurement of the IMTT and the angle to be corrected in patients with and without hallux valgus
Methods: In this retrospective study 63 patients were included: 28 pts with HV (48 feet) 35 pts without HV (48 feet) Measurements: IMTT angle Angle to be corrected All measurements were made by 3 observers (TMT) All Rx were taken at the same center and using the same technique. The test of variances was used for statistical analysis
Results: Patients with HV: IMTT 13.62 (SD 3.31, variability coefficient 0.243) The difference between the observers was not significant. Angle to be corrected 8.91 (SD 3.74, variability coefficient 0.42 ) The difference between the observers was not significant The analysis of the variances between the two measurements was not significant.
Results: Pts without HV: IMTT 7.65 (SD 1.87, variability coefficient 0.244) The difference between the observers was not significant Angle to be corrected 3.56 (SD 1.49, variability coefficient 0.419) The difference between the observers was not significant The analysis of the variances between the two angles measured showed a greater variance in the IMTT angle
Discussion: The IMTT angle is a useful tool in the properative planning for the treatment of HV Mark E., et al. Current Concepts Review: Hallux Valgus Part II: Operative Treatment FAI 2007. Roger M., Disorders of the First Metatarsophalangeal Joint. JAAOS 1995. Robinson A., et al. Modern concepts in the treatment of hallux valgus. JBJS 2005 In HV the metatarsal head moves off the sling of the sesamoid and intersesamoid ligament Tanaka Y., et al. Precise anatomic configuration changes in the first ray of the hallux valgus foot. FAI 2000.
Conclusion: The angle to be corrected presents a similar interobserver variability as the IMTT angle, in hallux valgus and non-hallux valgus patients As this new angle is designed to be used in hallux valgus deformities, we think that it is a useful tool in the preoperative planning as it helps to choose the technique to use in a certain case
Bibliography: Wolfgang Sch., et al. Reproducibility of the radiographic metatersophalangeal angle in hallux surgery. JBJS Am. 2003 Wagner E., et al. Modified diaphyseal osteotomy with a proximal center of rotation for moderate to severe hallux valgus. TFAS 2007. Mark E., et al. Current Concepts Review: Hallux Valgus Part II: Operative Treatment FAI 2007. Roger M., Disorders of the First Metatarsophalangeal Joint. JAAOS 1995. Robinson A., et al. Modern concepts in the treatment of hallux valgus. JBJS 2005 Tanaka Y., et al. Precise anatomic configuration changes in the first ray of the hallux valgus foot. FAI 2000